A draughty door is one of the few home problems where a small amount of money and an hour of work produce an immediate, noticeable result. You feel the difference the same evening.
This guide covers how to find where the cold air is actually coming from, which type of draught proofing suits which gap, how to fit it correctly, what to do when it does not work, and when the honest answer is that the door itself needs replacing. Doors2Floors has supplied doors and flooring to homes and businesses across the UK, and draughts are one of the most common winter enquiries we receive.
One clarification first. The previous version of this article defined a draught excluder as a long fabric object placed in front of a door. That is a draught snake or door sausage, and it only helps at the bottom of a closed door. A fitted draught excluder is a compressible strip installed into the frame rebate that seals the whole perimeter. This guide is about the fitted kind, because that is what actually solves the problem.
Finding where the draught is coming from
The candle or incense test
On a windy day, close all windows, then move a lit incense stick slowly around the door perimeter. Where the smoke pulls sideways, air is moving. Keep naked flames away from curtains and never leave them unattended.
The paper test
Close the door on a sheet of paper. If it slides out without resistance at any point, there is no seal there.
The daylight test
Turn off the lights in the hall and have someone shine a torch around the closed door from the other side. Any light you can see is a gap.
The hand test
The back of the hand is far more sensitive to moving air than the palm. Run it slowly around the perimeter.
Check the letterbox
On a front door this is frequently the single largest opening in the whole assembly.
Check the keyhole and cylinder
An unshuttered keyhole on an older lock lets a surprising amount of air through.
Check the threshold
The gap under the door is usually the largest gap on any door, and it is where cold air enters fastest.
Do not forget the frame itself
Air often passes between the frame and the wall rather than between the door and the frame. Look behind the architrave before you buy any seals. Our architrave guide covers removing and refitting it.
What a fitted draught excluder actually does
The basic principle
A compressible strip fills the gap between the door edge and the frame, so that when the door closes, air can no longer pass through.
Heat loss versus perceived cold
Draughts feel much colder than the heat they actually carry away, because moving air strips warmth from your skin. Sealing them improves comfort more than the energy figures alone suggest.
External doors versus internal doors
External doors are about heat loss and comfort. Internal doors are about stopping cold air travelling between rooms and stopping heat escaping into unheated spaces.
The internal doors that matter most
Doors onto unheated hallways, doors to integral garages, loft hatches and doors to unused rooms. These are where internal draught proofing genuinely pays.
The limits of draught proofing
It will not fix a door that is warped, a frame that has moved, or a wall that is not insulated. It is a sealing measure, not a structural one.
Do not seal a house airtight
Homes need background ventilation to control moisture. Sealing every gap without keeping trickle vents and extractors working leads to condensation and mould.
Draught proofing and condensation
If you seal a draughty room and then find condensation on the windows, the moisture was always there and the draught was carrying it away. Improve ventilation deliberately rather than accidentally.
Draught proofing and swollen doors
Adding a thick seal to a door that already binds makes it worse. Sort the fit first. Our guide to stopping doors swelling and sticking covers diagnosis.
Types of draught proofing and where each belongs
Self adhesive foam strip
The cheapest option. Easy to fit, but it compresses permanently and usually needs replacing every year or two. Fine as a first attempt or in a rented property.
E profile rubber strip
For small gaps, roughly 2mm to 3.5mm. Good recovery and a realistic life of several years.
P profile rubber strip
For medium gaps, roughly 3mm to 5mm. The most widely useful profile in UK homes.
V profile or tension seal
A folded strip that springs open against the door. Almost invisible when fitted and excellent on sash windows and older frames.
Brush pile strip
A row of dense bristle in a carrier. It copes with uneven gaps and with doors that move, and it is the right choice where a rubber seal would bind.
Silicone tube seal
Fitted into a machined groove in the frame. It is the most durable option and the one most often specified on new joinery.
Compression seals for rebated frames
Where the frame has a rebate, a seal fitted into the rebate is neater and lasts longer than a surface applied strip.
Choosing by gap size, not by price
Measure the gap with a folded piece of card or a feeler gauge. A seal that is too thick makes the door hard to close; too thin and it does nothing.
Sealing the bottom of the door
Why the bottom matters most
It is normally the biggest gap and the lowest point, so cold air pours in there while warm air escapes higher up.
Brush strip bottom seals
Screwed or stuck to the face of the door at the bottom. Cheap, effective, and forgiving of an uneven floor.
Drop down seals
A concealed seal that lowers automatically when the door closes and lifts when it opens. The best performing option and the most expensive.
Threshold strips and weather bars
Fitted to the floor rather than the door. They work well but create a small trip step, so consider who uses the door.
Rain deflectors on external doors
A drip bar on the outside face throws water clear of the bottom edge and protects the timber as well as the draught seal.
Carpet and threshold interaction
A brush strip dragging on carpet wears out quickly and makes the door heavy to open. Measure the clearance over the finished floor.
Do not just block the gap with a fabric snake
A door sausage works only while the door is closed and it does nothing for the sides or the top. It is a stopgap, not a fix.
Fire doors and bottom seals
Fire doors have specific requirements for gaps and seals. Never fit a generic bottom seal to a fire door without checking. We list FD30 fire doors, and requirements should be confirmed with your local building control body.
What you will need
Measuring tools
A tape measure and something to gauge the gap. Card folded to a known thickness works perfectly well.
The seal itself
Buy more than you think. A standard internal door needs roughly 5 metres for the two sides and the head.
Cutting tools
Sharp scissors for foam and brush, a craft knife for rubber profiles, and a small hacksaw for aluminium carriers.
Cleaning materials
Sugar soap or methylated spirit and a lint free cloth. Adhesive backed seals fail on dusty or greasy timber.
Fixings
Screwed seals need a bradawl or a small pilot drill. Do not drive screws into hardwood without piloting.
A screwdriver and pencil
For marking positions and for adjusting the strike plate afterwards if needed.
Optional, a hinge packer
Thin card or plastic packers behind a hinge leaf let you shift the door slightly to even out the gap.
Optional, new hardware
A letterbox draught excluder, a keyhole cover or an escutcheon with a shutter. Browse door handles and locks and latches.
How to fit a draught excluder step by step
Step one, measure the gap all the way round
Gaps are rarely even. Measure at the top, middle and bottom of each side, and at both ends of the head.
Step two, choose the profile
Match the seal thickness to the largest gap you need to close, not the smallest, and be ready to use two profiles on one door.
Step three, clean the surface
Wash and dry the rebate thoroughly. This is the step that decides whether a self adhesive seal is still there next winter.
Step four, start at the top
Fit the head first, running the full width. Press firmly along the whole length rather than just at the ends.
Step five, do the hinge side
Run the seal from the head down to the floor. Cut around each hinge rather than over it, and never pack the seal into the hinge knuckle.
Step six, do the latch side
Same again, cutting neatly around the strike plate. Butt the ends against the head strip rather than overlapping them.
Step seven, cut to length accurately
Measure and cut with the seal in place. Cutting short leaves a gap exactly where the corner draught is worst.
Step eight, test the door
Close it. It should meet slight resistance and then latch normally. If it will not latch, the seal is too thick or the strike plate needs moving.
Working around awkward doors
Doors with uneven gaps
Use a brush strip, which tolerates variation far better than rubber. Alternatively pack a hinge to even the gap first.
Arched and curved heads
Use a flexible foam or brush strip and fit it in short sections rather than one length.
Doors with no rebate
A flat frame needs a surface mounted seal on the stop, or a planted stop repositioned to suit.
Very old and out of square frames
Brush pile is almost always the answer. A rubber profile that seals at the top will bind at the bottom.
Glazed doors
Check the glazing bead seals too. A loose bead lets air past the glass. We stock glazed doors if the beadwork has failed completely.
Sliding and pocket doors
These need brush seals rather than compression seals, because a compression seal makes them impossible to slide. We list sliding door kit systems and pocket doors.
Bi-fold doors
Multiple leaves mean multiple edges and more air paths. Our bi-fold door guide explains the trade off, and we stock bi-fold doors.
French doors and door pairs
The meeting stile between the two leaves needs its own seal, usually a brush or a rebated compression strip. See our French doors guide.
Checking whether it worked
Repeat the smoke test
Do it on a windy day with the windows shut, the same conditions as your original test.
Repeat the paper test
The paper should now grip firmly at every point around the perimeter.
Listen
Whistling around a door frame stops immediately once the seal is right. Noise reduction is a good proxy for airtightness.
Feel the room
Cold ankles in a hallway is the classic symptom. If it is gone, the bottom seal is working.
Watch the thermostat
A well sealed room reaches temperature faster and holds it longer.
Check the door still operates properly
It should close with a light push and latch cleanly. A door you have to shoulder is over sealed.
Recheck after a month
Foam seals compress and adhesive can lift. A quick check after four weeks catches problems early.
Recheck each autumn
Make it part of the same routine as clearing gutters and testing extractor fans.
Troubleshooting common problems
The door will not latch any more
The seal is too thick, or the strike plate needs moving out a millimetre or two. Move the plate before you change the seal.
The seal has peeled off
Almost always inadequate cleaning. Remove it entirely, degrease properly and refit with a fresh strip.
The door now slams
Compressing air behind a sealed door creates pressure. A soft close hinge or a door closer with adjustable tension helps. See our notes on doors slamming.
Still draughty at one corner
The frame is out of square at that corner. Pack a hinge or use a thicker profile on that side only.
Draught coming through the wall, not the door
Remove the architrave and check for gaps between the frame and the masonry. Fill with expanding foam or mastic and refit. We stock architrave products.
Condensation has appeared since sealing
The moisture was always being produced; the draught was removing it. Improve extraction and keep trickle vents open.
The seal squeaks
Rubber against painted timber can squeak. A light wipe of silicone spray on the seal, not on the door, usually cures it.
The door is now stiff to open
Over sealed. Step down one profile thickness or switch to a brush strip.
Draughts from the letterbox, keyhole and cat flap
Letterbox draught excluders
A twin brush unit fitted behind the letterplate. On many front doors this is the single biggest improvement available.
Letterbox size and post
Make sure the brush unit still allows normal post through. Very stiff brushes cause complaints from the postal service.
Keyhole covers
An escutcheon with a pivoting cover closes the keyhole when it is not in use.
Euro cylinder gaps
Gaps around the cylinder on a composite or uPVC door are usually a fitting issue. Check the cylinder is the right length before sealing.
Cat flaps
Older flaps leak badly. Modern magnetic and microchip flaps seal far better.
Old ventilation grilles in doors
Some older doors have purpose fitted vents. Check whether they serve a gas appliance before blocking anything.
Redundant door furniture holes
Old handle and lock holes let air through. Fill them properly rather than covering them with a plate.
Glazing bead gaps
Reseal or replace failed beads. This is common on older glazed front doors.
When the door itself is the problem
Warped or twisted leaves
No seal will close a gap caused by a twisted door. Replacement is the honest answer.
Doors trimmed too far
A door cut down for an old carpet will never seal against a new floor. Our guide on planing a door explains the limits.
Hollow core doors on external openings
These should never be used externally. Our comparison of hollow core versus solid core doors explains why.
Single glazed door panels
Old single glazed panels lose far more heat than the draught around the frame. Our U values guide explains the numbers.
Rotten frames and thresholds
Soft timber at the bottom of a frame cannot hold a seal. Replace the frame. We list internal frames and external frames.
Composite doors as an upgrade
A modern composite door arrives with multi point locking and factory fitted seals. We stock composite external doors. See our grey composite door guide.
Timber external doors
Still the right choice on many period properties, but they need maintenance. We list external doors and glazed external doors, and our wooden front door care guide covers upkeep.
Replacing internal doors
A new, correctly hung door with a proper lining seals far better than an old one with strips added. Browse internal doors.
Other ways to keep your home warmer
Loft insulation
The highest value insulation upgrade in most UK houses. Note that in British usage this space is a loft, not an attic.
Cavity and solid wall insulation
Significant work with significant returns. Always use an installer with the appropriate certification.
Floor draughts
Suspended timber floors leak air between the boards. Sealing gaps and fitting underlay under a new floor helps considerably. See our engineered oak flooring guide and our flooring range.
Curtains and blinds
Thick, lined, floor length curtains cut heat loss through windows noticeably. Draw them at dusk rather than at bedtime.
A curtain over the front door
A traditional and very effective solution in older houses, especially where the front door opens straight into a living room.
Chimneys and open fireplaces
An unused open chimney is often a larger air leak than every door in the house combined. Use a removable chimney balloon rather than sealing it permanently.
Radiator reflectors and shelves
Cheap, and genuinely useful on external walls.
Secondary glazing
The standard UK solution where windows cannot be replaced, particularly in listed buildings and conservation areas.
Internal doors as zoning
Closing off unheated rooms costs nothing. Our room dividers let you do the same in an open plan space.
Draught proofing room by room
Front door and entrance hall
The highest priority in almost every UK home. Seal the perimeter, the threshold, the letterbox and the keyhole, and consider a curtain. Browse external doors if the leaf itself is past saving.
Back door and utility
Often the worst fitting door in the house because it gets the heaviest use. Brush strips cope best with the wear.
Integral garage door
Cold, and usually required to be a fire door. Never fit generic seals here. We list FD30 fire doors, FD60 fire doors and glazed fire doors. See what fire doors are and where they go and fire door materials.
Loft hatch
A frequently overlooked route for warm air to escape upwards. An insulated, sealed hatch is inexpensive and effective.
Understairs cupboard
Often connects to unheated floor voids. Sealing it stops cold air being drawn into the hall.
Living room door
Worth sealing where it opens onto an unheated hall. A glazed door from our over 280 options keeps light flowing while retaining the seal.
Bedroom doors
Low priority for heat, but useful for noise. A solid core door plus perimeter seals makes a real acoustic difference. Our unglazed doors include solid options.
Bathroom and en suite doors
Be careful here. Over sealing a bathroom traps moisture. Seal the bottom and leave the extraction working hard.
Conservatory doors
The largest temperature difference of any internal opening in a UK home. Our conservatory guide covers the wider issues.
Home office and study
Sealing improves both warmth and acoustics for calls. See our guide to internal doors for modern UK homes.
Choosing replacement doors that seal well
Fully finished doors in an accurately fitted lining seal best. We list fully finished internal doors and white primed internal doors, starting at £55.99. Our buyers guide covers the decisions.
Oak and timber options
If you want timber, our internal oak doors include the LPD Girona Fully Finished Oak at £150.00. See our door materials guide.
Hardware that helps
Correctly adjusted hinges and keeps do as much as any seal. We stock door hinges, handle packs and door stops. See our hinge positioning guide and our loose handle guide.
Costs and what to expect
Self adhesive foam
The cheapest per metre and the shortest lived. Budget to replace it annually.
Rubber profiles
A modest step up in cost for several years of service. The best value for most households.
Brush strips and carriers
More expensive, particularly with an aluminium carrier, but very durable.
Drop down seals
The most expensive option and the best performing. Usually reserved for external doors and acoustic applications.
Letterbox and keyhole hardware
Small individual costs with a disproportionate effect on comfort.
Paying someone to do it
A joiner will do a whole house in a day. That is usually good value if you have several awkward openings.
Replacing the door instead
Our clearance doors and our guide to internal door fitting costs help you compare.
Payback
Draught proofing is one of the lowest cost, fastest payback measures available to a UK household. It also delivers comfort immediately, which insulation in a loft does not.
Frequently asked questions
What is a draught excluder?
A compressible strip fitted around a door frame that closes the gap between door and frame. It is different from a fabric draught snake, which only sits at the bottom of a closed door.
Which draught excluder should I buy?
Measure your gap first. E profile for small gaps, P profile for medium, brush pile for uneven or large gaps, and a brush or drop down seal for the bottom.
Can I fit one myself?
Yes. Self adhesive strips need no tools beyond scissors, and screwed brush strips need only a screwdriver and a bradawl.
How long does draught proofing last?
Foam typically one to two years, rubber profiles three to five, brush and silicone seals considerably longer.
Will draught proofing cause damp?
Only if you seal everything and remove your ventilation. Keep trickle vents open and run extractor fans properly.
Should I draught proof internal doors?
Yes, where a door separates heated from unheated space. There is little point sealing a door between two warm rooms.
Can I draught proof a fire door?
Fire doors have specified gaps and their own intumescent and smoke seals. Never add or replace seals on a fire door without checking. We stock fire doors with the correct seals specified.
My door still whistles after sealing. Why?
Air is finding another route, most often the letterbox, the keyhole or the gap between frame and wall behind the architrave.
Is it worth sealing an old single glazed door?
It helps with comfort, but the glass is losing most of the heat. Sealing is a stopgap before replacement.
Do draught excluders work on uPVC and composite doors?
Those doors have integral seals. If they are draughty, the usual fix is adjusting the hinges and keeps rather than adding strips.
Getting the best result
Diagnose before you buy
Ten minutes with an incense stick saves you buying the wrong profile twice.
Do the bottom of the door first
It is the biggest gap and gives the largest immediate improvement.
Do not neglect the frame to wall junction
It is hidden behind the architrave and it is frequently the real culprit.
Keep ventilation deliberate
Seal the gaps you do not want and keep the ones you do. Trickle vents and extractors are there for a reason.
Combine measures
Draught proofing plus curtains plus a chimney balloon costs very little together and transforms an old room.
Know when to stop sealing and start replacing
A warped, rotten or badly fitting door is not a sealing problem. Our guide to choosing the right door covers the alternatives.
Check the fit before winter, not during
Autumn is the right time. Our guide to measuring a door and our UK door sizes guide help if you are replacing.
Ask us
Send a photograph of the gap and the frame and we can usually tell you which profile to buy.
Prices and product counts quoted in this guide reflect our live listings at the time of writing and are subject to change. Never block ventilation serving a gas or solid fuel appliance, and seek advice from a registered engineer if in doubt. Fire door and building regulation requirements vary by property type and by nation within the UK, so confirm your obligations with your local building control body or a competent professional before altering seals on a fire door.